1. Field of the Invention
This invention relates to a wavefront flattener and, more particularly, to a unique and novel wavefront flattener which may be used in a radar test chamber which requires a very large angle simulation test array with thousands of RF elements wherein each element must radiate a wave which becomes essentially flat at a distance of 100 feet over an area of 450 square feet.
2. Description of the Prior Art
RF anechoic chambers are widely used for antenna pattern measuring and to a lesser extent for RF quiet areas for test and evaluation of missiles and radars which utilize antennas. These chambers are excellent test areas for smaller antenna systems. However, for larger and higher frequency devices, there is a serious limitation, i.e., a c-band 8 foot diameter antenna system would require a building 800 or more feet long. This problem is caused primarily by the curvature of the wavefront. Generally, the wavefront is flat enough when the range does not exceed two times the square of the diameter of the antenna divided by the wave length of the RF. In some instances, it is possible to use a very large lens or a parabolic section to collimate the wavefront to flatten it. However, these solutions are not satisfactory where a large device is not possible or is objectionable.